DE 10 2005 033 023 A1 discloses a heat exchanger device and a method for operating this heat exchanger device in a vehicle having an internal combustion engine, wherein an oil cooler and an exhaust gas recirculation cooler are integrated into the heat exchanger system, a cooling medium passing through the heat exchanger system, and heat flow being exchanged between oil, exhaust gas, and/or cooling medium, and are controlled as a function of operating states of the internal combustion engine in order to optimize emission of pollutants and fuel consumption.
A device is known from DE 197 50 588 for exhaust gas recirculation for an internal combustion engine, having an exhaust gas cooler and a valve which determines the quantity of exhaust gas recirculated and which is adjustable by means of an actuator, the exhaust gas cooler and the valve directly adjoining one another and forming a modular unit.
DE 103 51 845 B4 discloses an exhaust gas heat exchanger for cooling exhaust gas from an internal combustion engine, using a two-stage exhaust gas recirculation system. The cooling system has a high-temperature branch with coolant at a high temperature level, and has a low-temperature branch with coolant at a temperature lower than that of the coolant in the high-temperature branch. A high-temperature exhaust gas heat exchanger is provided in the high-temperature branch, and a low-temperature exhaust gas heat exchanger is provided in the low-temperature branch, and exhaust gas to be recooled passes through both in succession. Such an exhaust gas heat exchanger is described as being economical and space-saving, with optimal cooling of the exhaust gas.
The object of the present invention is to provide an exhaust gas line for an internal combustion engine by means of which an overall design for the exhaust gas recirculation system for a model series of internal combustion engines having different power ratings, and with different numbers of cylinders, is achieved for all applications, and for cooled and uncooled exhaust gas lines, with a minimum number of part variations for the exhaust gas recirculation system.
This object is achieved by use of an exhaust gas line for an internal combustion engine having the features of claim 1. Advantageous embodiments of the invention are stated in the subclaims.
According to the invention, an exhaust gas line for exhaust gas from at least one cylinder of an internal combustion engine has at least one collecting housing from which an exhaust gas recirculation system branches off. According to the invention, the collecting housing is designed as a section of the exhaust gas line for the internal combustion engine, with the advantage that, on account of integrating the collecting housing and exhaust gas line, the number of components for the exhaust gas line for a model series of the internal combustion engine having exhaust gas recirculation may be minimized for different power ratings and for different numbers of cylinders, and for all applications, resulting in cost and logistical advantages for the exhaust gas recirculation system with minimal modification effort for existing designs, and a minimal number of part variations.
According to one preferred embodiment of the invention, the collecting housing has an exhaust gas inlet which is designed as a flange for an exhaust gas outlet for the internal combustion engine.
According to a further preferred embodiment of the invention, the internal combustion engine has multiple cylinders in a V-shaped configuration, and the exhaust gas outlet for the internal combustion engine is situated between the cylinder heads, so that the collecting housing together with the integrated exhaust gas line and a respective branch to an exhaust gas recirculation system are advantageously located between the cylinder rows of an eight-cylinder V-8 internal combustion engine, for example, for an overall space-saving design.
According to a further preferred embodiment of the invention, each flange, which is rotatable by 180°, is provided between the collecting housing and an exhaust gas outlet on outwardly facing sides of the cylinder heads, so that by rotating the collecting housing relative to the cylinder head the position of the collecting housing together with the integrated exhaust gas line and a respective branch to an exhaust gas recirculation system may be specified in a flexible manner which is the most advantageous for an overall space-saving configuration.
According to a further preferred embodiment of the invention, the collecting housing has an additional connection for recirculated exhaust gas to an air intake for the internal combustion engine.
According to a further preferred embodiment of the invention, the collecting housings integrated into the exhaust gas line are provided with lateral surfaces which are at least partially congruent so that collecting housings may be installed in succession, thereby allowing the number of branches to exhaust gas recirculation systems to be varied as needed.
According to a further preferred embodiment of the invention, the width of a collecting housing corresponds to the width of a cylinder of the internal combustion engine, thus allowing the collecting housing to be positioned in parallel with cylinders of the internal combustion engine.
According to a further preferred embodiment of the invention, the exhaust gas recirculation system is provided with a deflector housing for compact recirculation of the exhaust gas.
According to a further preferred embodiment of the invention, the exhaust gas recirculation system is provided with heat exchangers for cooling recirculated exhaust gas, thereby optimizing emission of pollutants and fuel consumption of the internal combustion engine. According to a further preferred embodiment of the invention, the collecting housing and deflector housing are integrated into the cooling system in order to reduce thermal stress.
According to a further preferred embodiment of the invention, the heat exchangers, in particular three heat exchangers, are connected in series for increased thermal output.
According to a further preferred embodiment of the invention, the heat exchangers, in particular three heat exchangers, are connected in parallel in order to minimize pressure losses and to provide uniform load on the heat exchangers.
According to a further preferred embodiment of the invention, two heat exchangers are connected in parallel and one heat exchanger is connected thereto in series, resulting in an optimal compromise regarding thermal output, pressure losses, and stress on the heat exchangers.
According to a further preferred embodiment of the invention, the collecting housing is provided with an exhaust gas recirculation butterfly valve which is connected directly to the exhaust gas heat exchanger and is provided between the cylindrical chamber of the collecting housing and the exhaust gas line to the turbine of the turbocharger, in an essentially cylindrical exhaust gas recirculation duct in the form of a centrally pivotable switching valve.
According to a further preferred embodiment of the invention, an inner cross section of the exhaust gas line is provided with profiles with tapering cross sections in order to produce a linearized flow characteristic curve for the exhaust gas.
According to a further preferred embodiment of the invention, the profiles with tapering cross sections are patterned as circular segments whose respective midpoints lie outside the center of rotation of the switching valve, and whose radii are larger than the switching valve.
According to a further preferred embodiment of the invention, the exhaust gas recirculation butterfly valve is designed as a switching valve or a rotary valve, and is mechanically connected to a controller which is preferably actuated by compressed air.
According to a further preferred embodiment of the invention, leak discharge outlets are provided in the deflector housing to avoid backflow of leaking fluid to the cylinders of the internal combustion engine.